| /* |
| * linux/fs/fcntl.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| */ |
| |
| #include <linux/syscalls.h> |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/fs.h> |
| #include <linux/file.h> |
| #include <linux/fdtable.h> |
| #include <linux/capability.h> |
| #include <linux/dnotify.h> |
| #include <linux/slab.h> |
| #include <linux/module.h> |
| #include <linux/pipe_fs_i.h> |
| #include <linux/security.h> |
| #include <linux/ptrace.h> |
| #include <linux/signal.h> |
| #include <linux/rcupdate.h> |
| #include <linux/pid_namespace.h> |
| |
| #include <asm/poll.h> |
| #include <asm/siginfo.h> |
| #include <asm/uaccess.h> |
| |
| void set_close_on_exec(unsigned int fd, int flag) |
| { |
| struct files_struct *files = current->files; |
| struct fdtable *fdt; |
| spin_lock(&files->file_lock); |
| fdt = files_fdtable(files); |
| if (flag) |
| __set_close_on_exec(fd, fdt); |
| else |
| __clear_close_on_exec(fd, fdt); |
| spin_unlock(&files->file_lock); |
| } |
| |
| static bool get_close_on_exec(unsigned int fd) |
| { |
| struct files_struct *files = current->files; |
| struct fdtable *fdt; |
| bool res; |
| rcu_read_lock(); |
| fdt = files_fdtable(files); |
| res = close_on_exec(fd, fdt); |
| rcu_read_unlock(); |
| return res; |
| } |
| |
| SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags) |
| { |
| int err = -EBADF; |
| struct file * file, *tofree; |
| struct files_struct * files = current->files; |
| struct fdtable *fdt; |
| |
| if ((flags & ~O_CLOEXEC) != 0) |
| return -EINVAL; |
| |
| if (unlikely(oldfd == newfd)) |
| return -EINVAL; |
| |
| spin_lock(&files->file_lock); |
| err = expand_files(files, newfd); |
| file = fcheck(oldfd); |
| if (unlikely(!file)) |
| goto Ebadf; |
| if (unlikely(err < 0)) { |
| if (err == -EMFILE) |
| goto Ebadf; |
| goto out_unlock; |
| } |
| /* |
| * We need to detect attempts to do dup2() over allocated but still |
| * not finished descriptor. NB: OpenBSD avoids that at the price of |
| * extra work in their equivalent of fget() - they insert struct |
| * file immediately after grabbing descriptor, mark it larval if |
| * more work (e.g. actual opening) is needed and make sure that |
| * fget() treats larval files as absent. Potentially interesting, |
| * but while extra work in fget() is trivial, locking implications |
| * and amount of surgery on open()-related paths in VFS are not. |
| * FreeBSD fails with -EBADF in the same situation, NetBSD "solution" |
| * deadlocks in rather amusing ways, AFAICS. All of that is out of |
| * scope of POSIX or SUS, since neither considers shared descriptor |
| * tables and this condition does not arise without those. |
| */ |
| err = -EBUSY; |
| fdt = files_fdtable(files); |
| tofree = fdt->fd[newfd]; |
| if (!tofree && fd_is_open(newfd, fdt)) |
| goto out_unlock; |
| get_file(file); |
| rcu_assign_pointer(fdt->fd[newfd], file); |
| __set_open_fd(newfd, fdt); |
| if (flags & O_CLOEXEC) |
| __set_close_on_exec(newfd, fdt); |
| else |
| __clear_close_on_exec(newfd, fdt); |
| spin_unlock(&files->file_lock); |
| |
| if (tofree) |
| filp_close(tofree, files); |
| |
| return newfd; |
| |
| Ebadf: |
| err = -EBADF; |
| out_unlock: |
| spin_unlock(&files->file_lock); |
| return err; |
| } |
| |
| SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd) |
| { |
| if (unlikely(newfd == oldfd)) { /* corner case */ |
| struct files_struct *files = current->files; |
| int retval = oldfd; |
| |
| rcu_read_lock(); |
| if (!fcheck_files(files, oldfd)) |
| retval = -EBADF; |
| rcu_read_unlock(); |
| return retval; |
| } |
| return sys_dup3(oldfd, newfd, 0); |
| } |
| |
| SYSCALL_DEFINE1(dup, unsigned int, fildes) |
| { |
| int ret = -EBADF; |
| struct file *file = fget_raw(fildes); |
| |
| if (file) { |
| ret = get_unused_fd(); |
| if (ret >= 0) |
| fd_install(ret, file); |
| else |
| fput(file); |
| } |
| return ret; |
| } |
| |
| #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) |
| |
| static int setfl(int fd, struct file * filp, unsigned long arg) |
| { |
| struct inode * inode = filp->f_path.dentry->d_inode; |
| int error = 0; |
| |
| /* |
| * O_APPEND cannot be cleared if the file is marked as append-only |
| * and the file is open for write. |
| */ |
| if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) |
| return -EPERM; |
| |
| /* O_NOATIME can only be set by the owner or superuser */ |
| if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) |
| if (!inode_owner_or_capable(inode)) |
| return -EPERM; |
| |
| /* required for strict SunOS emulation */ |
| if (O_NONBLOCK != O_NDELAY) |
| if (arg & O_NDELAY) |
| arg |= O_NONBLOCK; |
| |
| if (arg & O_DIRECT) { |
| if (!filp->f_mapping || !filp->f_mapping->a_ops || |
| !filp->f_mapping->a_ops->direct_IO) |
| return -EINVAL; |
| } |
| |
| if (filp->f_op && filp->f_op->check_flags) |
| error = filp->f_op->check_flags(arg); |
| if (error) |
| return error; |
| |
| /* |
| * ->fasync() is responsible for setting the FASYNC bit. |
| */ |
| if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op && |
| filp->f_op->fasync) { |
| error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); |
| if (error < 0) |
| goto out; |
| if (error > 0) |
| error = 0; |
| } |
| spin_lock(&filp->f_lock); |
| filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); |
| spin_unlock(&filp->f_lock); |
| |
| out: |
| return error; |
| } |
| |
| static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, |
| int force) |
| { |
| write_lock_irq(&filp->f_owner.lock); |
| if (force || !filp->f_owner.pid) { |
| put_pid(filp->f_owner.pid); |
| filp->f_owner.pid = get_pid(pid); |
| filp->f_owner.pid_type = type; |
| |
| if (pid) { |
| const struct cred *cred = current_cred(); |
| filp->f_owner.uid = cred->uid; |
| filp->f_owner.euid = cred->euid; |
| } |
| } |
| write_unlock_irq(&filp->f_owner.lock); |
| } |
| |
| int __f_setown(struct file *filp, struct pid *pid, enum pid_type type, |
| int force) |
| { |
| int err; |
| |
| err = security_file_set_fowner(filp); |
| if (err) |
| return err; |
| |
| f_modown(filp, pid, type, force); |
| return 0; |
| } |
| EXPORT_SYMBOL(__f_setown); |
| |
| int f_setown(struct file *filp, unsigned long arg, int force) |
| { |
| enum pid_type type; |
| struct pid *pid; |
| int who = arg; |
| int result; |
| type = PIDTYPE_PID; |
| if (who < 0) { |
| type = PIDTYPE_PGID; |
| who = -who; |
| } |
| rcu_read_lock(); |
| pid = find_vpid(who); |
| result = __f_setown(filp, pid, type, force); |
| rcu_read_unlock(); |
| return result; |
| } |
| EXPORT_SYMBOL(f_setown); |
| |
| void f_delown(struct file *filp) |
| { |
| f_modown(filp, NULL, PIDTYPE_PID, 1); |
| } |
| |
| pid_t f_getown(struct file *filp) |
| { |
| pid_t pid; |
| read_lock(&filp->f_owner.lock); |
| pid = pid_vnr(filp->f_owner.pid); |
| if (filp->f_owner.pid_type == PIDTYPE_PGID) |
| pid = -pid; |
| read_unlock(&filp->f_owner.lock); |
| return pid; |
| } |
| |
| static int f_setown_ex(struct file *filp, unsigned long arg) |
| { |
| struct f_owner_ex * __user owner_p = (void * __user)arg; |
| struct f_owner_ex owner; |
| struct pid *pid; |
| int type; |
| int ret; |
| |
| ret = copy_from_user(&owner, owner_p, sizeof(owner)); |
| if (ret) |
| return -EFAULT; |
| |
| switch (owner.type) { |
| case F_OWNER_TID: |
| type = PIDTYPE_MAX; |
| break; |
| |
| case F_OWNER_PID: |
| type = PIDTYPE_PID; |
| break; |
| |
| case F_OWNER_PGRP: |
| type = PIDTYPE_PGID; |
| break; |
| |
| default: |
| return -EINVAL; |
| } |
| |
| rcu_read_lock(); |
| pid = find_vpid(owner.pid); |
| if (owner.pid && !pid) |
| ret = -ESRCH; |
| else |
| ret = __f_setown(filp, pid, type, 1); |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| |
| static int f_getown_ex(struct file *filp, unsigned long arg) |
| { |
| struct f_owner_ex * __user owner_p = (void * __user)arg; |
| struct f_owner_ex owner; |
| int ret = 0; |
| |
| read_lock(&filp->f_owner.lock); |
| owner.pid = pid_vnr(filp->f_owner.pid); |
| switch (filp->f_owner.pid_type) { |
| case PIDTYPE_MAX: |
| owner.type = F_OWNER_TID; |
| break; |
| |
| case PIDTYPE_PID: |
| owner.type = F_OWNER_PID; |
| break; |
| |
| case PIDTYPE_PGID: |
| owner.type = F_OWNER_PGRP; |
| break; |
| |
| default: |
| WARN_ON(1); |
| ret = -EINVAL; |
| break; |
| } |
| read_unlock(&filp->f_owner.lock); |
| |
| if (!ret) { |
| ret = copy_to_user(owner_p, &owner, sizeof(owner)); |
| if (ret) |
| ret = -EFAULT; |
| } |
| return ret; |
| } |
| |
| static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, |
| struct file *filp) |
| { |
| long err = -EINVAL; |
| |
| switch (cmd) { |
| case F_DUPFD: |
| case F_DUPFD_CLOEXEC: |
| if (arg >= rlimit(RLIMIT_NOFILE)) |
| break; |
| err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0); |
| if (err >= 0) { |
| get_file(filp); |
| fd_install(err, filp); |
| } |
| break; |
| case F_GETFD: |
| err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; |
| break; |
| case F_SETFD: |
| err = 0; |
| set_close_on_exec(fd, arg & FD_CLOEXEC); |
| break; |
| case F_GETFL: |
| err = filp->f_flags; |
| break; |
| case F_SETFL: |
| err = setfl(fd, filp, arg); |
| break; |
| #if BITS_PER_LONG != 32 |
| /* 32-bit arches must use fcntl64() */ |
| case F_OFD_GETLK: |
| #endif |
| case F_GETLK: |
| err = fcntl_getlk(filp, cmd, (struct flock __user *) arg); |
| break; |
| #if BITS_PER_LONG != 32 |
| /* 32-bit arches must use fcntl64() */ |
| case F_OFD_SETLK: |
| case F_OFD_SETLKW: |
| #endif |
| /* Fallthrough */ |
| case F_SETLK: |
| case F_SETLKW: |
| err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg); |
| break; |
| case F_GETOWN: |
| /* |
| * XXX If f_owner is a process group, the |
| * negative return value will get converted |
| * into an error. Oops. If we keep the |
| * current syscall conventions, the only way |
| * to fix this will be in libc. |
| */ |
| err = f_getown(filp); |
| force_successful_syscall_return(); |
| break; |
| case F_SETOWN: |
| err = f_setown(filp, arg, 1); |
| break; |
| case F_GETOWN_EX: |
| err = f_getown_ex(filp, arg); |
| break; |
| case F_SETOWN_EX: |
| err = f_setown_ex(filp, arg); |
| break; |
| case F_GETSIG: |
| err = filp->f_owner.signum; |
| break; |
| case F_SETSIG: |
| /* arg == 0 restores default behaviour. */ |
| if (!valid_signal(arg)) { |
| break; |
| } |
| err = 0; |
| filp->f_owner.signum = arg; |
| break; |
| case F_GETLEASE: |
| err = fcntl_getlease(filp); |
| break; |
| case F_SETLEASE: |
| err = fcntl_setlease(fd, filp, arg); |
| break; |
| case F_NOTIFY: |
| err = fcntl_dirnotify(fd, filp, arg); |
| break; |
| case F_SETPIPE_SZ: |
| case F_GETPIPE_SZ: |
| err = pipe_fcntl(filp, cmd, arg); |
| break; |
| default: |
| break; |
| } |
| return err; |
| } |
| |
| static int check_fcntl_cmd(unsigned cmd) |
| { |
| switch (cmd) { |
| case F_DUPFD: |
| case F_DUPFD_CLOEXEC: |
| case F_GETFD: |
| case F_SETFD: |
| case F_GETFL: |
| return 1; |
| } |
| return 0; |
| } |
| |
| SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) |
| { |
| struct file *filp; |
| long err = -EBADF; |
| |
| filp = fget_raw(fd); |
| if (!filp) |
| goto out; |
| |
| if (unlikely(filp->f_mode & FMODE_PATH)) { |
| if (!check_fcntl_cmd(cmd)) { |
| fput(filp); |
| goto out; |
| } |
| } |
| |
| err = security_file_fcntl(filp, cmd, arg); |
| if (err) { |
| fput(filp); |
| return err; |
| } |
| |
| err = do_fcntl(fd, cmd, arg, filp); |
| |
| fput(filp); |
| out: |
| return err; |
| } |
| |
| #if BITS_PER_LONG == 32 |
| SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, |
| unsigned long, arg) |
| { |
| struct file * filp; |
| long err; |
| |
| err = -EBADF; |
| filp = fget_raw(fd); |
| if (!filp) |
| goto out; |
| |
| if (unlikely(filp->f_mode & FMODE_PATH)) { |
| if (!check_fcntl_cmd(cmd)) { |
| fput(filp); |
| goto out; |
| } |
| } |
| |
| err = security_file_fcntl(filp, cmd, arg); |
| if (err) { |
| fput(filp); |
| return err; |
| } |
| err = -EBADF; |
| |
| switch (cmd) { |
| case F_GETLK64: |
| case F_OFD_GETLK: |
| err = fcntl_getlk64(filp, cmd, (struct flock64 __user *) arg); |
| break; |
| case F_SETLK64: |
| case F_SETLKW64: |
| case F_OFD_SETLK: |
| case F_OFD_SETLKW: |
| err = fcntl_setlk64(fd, filp, cmd, |
| (struct flock64 __user *) arg); |
| break; |
| default: |
| err = do_fcntl(fd, cmd, arg, filp); |
| break; |
| } |
| fput(filp); |
| out: |
| return err; |
| } |
| #endif |
| |
| /* Table to convert sigio signal codes into poll band bitmaps */ |
| |
| static const long band_table[NSIGPOLL] = { |
| POLLIN | POLLRDNORM, /* POLL_IN */ |
| POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ |
| POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ |
| POLLERR, /* POLL_ERR */ |
| POLLPRI | POLLRDBAND, /* POLL_PRI */ |
| POLLHUP | POLLERR /* POLL_HUP */ |
| }; |
| |
| static inline int sigio_perm(struct task_struct *p, |
| struct fown_struct *fown, int sig) |
| { |
| const struct cred *cred; |
| int ret; |
| |
| rcu_read_lock(); |
| cred = __task_cred(p); |
| ret = ((fown->euid == 0 || |
| fown->euid == cred->suid || fown->euid == cred->uid || |
| fown->uid == cred->suid || fown->uid == cred->uid) && |
| !security_file_send_sigiotask(p, fown, sig)); |
| rcu_read_unlock(); |
| return ret; |
| } |
| |
| static void send_sigio_to_task(struct task_struct *p, |
| struct fown_struct *fown, |
| int fd, int reason, int group) |
| { |
| /* |
| * F_SETSIG can change ->signum lockless in parallel, make |
| * sure we read it once and use the same value throughout. |
| */ |
| int signum = ACCESS_ONCE(fown->signum); |
| |
| if (!sigio_perm(p, fown, signum)) |
| return; |
| |
| switch (signum) { |
| siginfo_t si; |
| default: |
| /* Queue a rt signal with the appropriate fd as its |
| value. We use SI_SIGIO as the source, not |
| SI_KERNEL, since kernel signals always get |
| delivered even if we can't queue. Failure to |
| queue in this case _should_ be reported; we fall |
| back to SIGIO in that case. --sct */ |
| si.si_signo = signum; |
| si.si_errno = 0; |
| si.si_code = reason; |
| /* Make sure we are called with one of the POLL_* |
| reasons, otherwise we could leak kernel stack into |
| userspace. */ |
| BUG_ON((reason & __SI_MASK) != __SI_POLL); |
| if (reason - POLL_IN >= NSIGPOLL) |
| si.si_band = ~0L; |
| else |
| si.si_band = band_table[reason - POLL_IN]; |
| si.si_fd = fd; |
| if (!do_send_sig_info(signum, &si, p, group)) |
| break; |
| /* fall-through: fall back on the old plain SIGIO signal */ |
| case 0: |
| do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group); |
| } |
| } |
| |
| void send_sigio(struct fown_struct *fown, int fd, int band) |
| { |
| struct task_struct *p; |
| enum pid_type type; |
| struct pid *pid; |
| int group = 1; |
| |
| read_lock(&fown->lock); |
| |
| type = fown->pid_type; |
| if (type == PIDTYPE_MAX) { |
| group = 0; |
| type = PIDTYPE_PID; |
| } |
| |
| pid = fown->pid; |
| if (!pid) |
| goto out_unlock_fown; |
| |
| read_lock(&tasklist_lock); |
| do_each_pid_task(pid, type, p) { |
| send_sigio_to_task(p, fown, fd, band, group); |
| } while_each_pid_task(pid, type, p); |
| read_unlock(&tasklist_lock); |
| out_unlock_fown: |
| read_unlock(&fown->lock); |
| } |
| |
| static void send_sigurg_to_task(struct task_struct *p, |
| struct fown_struct *fown, int group) |
| { |
| if (sigio_perm(p, fown, SIGURG)) |
| do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group); |
| } |
| |
| int send_sigurg(struct fown_struct *fown) |
| { |
| struct task_struct *p; |
| enum pid_type type; |
| struct pid *pid; |
| int group = 1; |
| int ret = 0; |
| |
| read_lock(&fown->lock); |
| |
| type = fown->pid_type; |
| if (type == PIDTYPE_MAX) { |
| group = 0; |
| type = PIDTYPE_PID; |
| } |
| |
| pid = fown->pid; |
| if (!pid) |
| goto out_unlock_fown; |
| |
| ret = 1; |
| |
| read_lock(&tasklist_lock); |
| do_each_pid_task(pid, type, p) { |
| send_sigurg_to_task(p, fown, group); |
| } while_each_pid_task(pid, type, p); |
| read_unlock(&tasklist_lock); |
| out_unlock_fown: |
| read_unlock(&fown->lock); |
| return ret; |
| } |
| |
| static DEFINE_SPINLOCK(fasync_lock); |
| static struct kmem_cache *fasync_cache __read_mostly; |
| |
| static void fasync_free_rcu(struct rcu_head *head) |
| { |
| kmem_cache_free(fasync_cache, |
| container_of(head, struct fasync_struct, fa_rcu)); |
| } |
| |
| /* |
| * Remove a fasync entry. If successfully removed, return |
| * positive and clear the FASYNC flag. If no entry exists, |
| * do nothing and return 0. |
| * |
| * NOTE! It is very important that the FASYNC flag always |
| * match the state "is the filp on a fasync list". |
| * |
| */ |
| int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) |
| { |
| struct fasync_struct *fa, **fp; |
| int result = 0; |
| |
| spin_lock(&filp->f_lock); |
| spin_lock(&fasync_lock); |
| for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
| if (fa->fa_file != filp) |
| continue; |
| |
| spin_lock_irq(&fa->fa_lock); |
| fa->fa_file = NULL; |
| spin_unlock_irq(&fa->fa_lock); |
| |
| *fp = fa->fa_next; |
| call_rcu(&fa->fa_rcu, fasync_free_rcu); |
| filp->f_flags &= ~FASYNC; |
| result = 1; |
| break; |
| } |
| spin_unlock(&fasync_lock); |
| spin_unlock(&filp->f_lock); |
| return result; |
| } |
| |
| struct fasync_struct *fasync_alloc(void) |
| { |
| return kmem_cache_alloc(fasync_cache, GFP_KERNEL); |
| } |
| |
| /* |
| * NOTE! This can be used only for unused fasync entries: |
| * entries that actually got inserted on the fasync list |
| * need to be released by rcu - see fasync_remove_entry. |
| */ |
| void fasync_free(struct fasync_struct *new) |
| { |
| kmem_cache_free(fasync_cache, new); |
| } |
| |
| /* |
| * Insert a new entry into the fasync list. Return the pointer to the |
| * old one if we didn't use the new one. |
| * |
| * NOTE! It is very important that the FASYNC flag always |
| * match the state "is the filp on a fasync list". |
| */ |
| struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new) |
| { |
| struct fasync_struct *fa, **fp; |
| |
| spin_lock(&filp->f_lock); |
| spin_lock(&fasync_lock); |
| for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
| if (fa->fa_file != filp) |
| continue; |
| |
| spin_lock_irq(&fa->fa_lock); |
| fa->fa_fd = fd; |
| spin_unlock_irq(&fa->fa_lock); |
| goto out; |
| } |
| |
| spin_lock_init(&new->fa_lock); |
| new->magic = FASYNC_MAGIC; |
| new->fa_file = filp; |
| new->fa_fd = fd; |
| new->fa_next = *fapp; |
| rcu_assign_pointer(*fapp, new); |
| filp->f_flags |= FASYNC; |
| |
| out: |
| spin_unlock(&fasync_lock); |
| spin_unlock(&filp->f_lock); |
| return fa; |
| } |
| |
| /* |
| * Add a fasync entry. Return negative on error, positive if |
| * added, and zero if did nothing but change an existing one. |
| */ |
| static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) |
| { |
| struct fasync_struct *new; |
| |
| new = fasync_alloc(); |
| if (!new) |
| return -ENOMEM; |
| |
| /* |
| * fasync_insert_entry() returns the old (update) entry if |
| * it existed. |
| * |
| * So free the (unused) new entry and return 0 to let the |
| * caller know that we didn't add any new fasync entries. |
| */ |
| if (fasync_insert_entry(fd, filp, fapp, new)) { |
| fasync_free(new); |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| /* |
| * fasync_helper() is used by almost all character device drivers |
| * to set up the fasync queue, and for regular files by the file |
| * lease code. It returns negative on error, 0 if it did no changes |
| * and positive if it added/deleted the entry. |
| */ |
| int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) |
| { |
| if (!on) |
| return fasync_remove_entry(filp, fapp); |
| return fasync_add_entry(fd, filp, fapp); |
| } |
| |
| EXPORT_SYMBOL(fasync_helper); |
| |
| /* |
| * rcu_read_lock() is held |
| */ |
| static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band) |
| { |
| while (fa) { |
| struct fown_struct *fown; |
| unsigned long flags; |
| |
| if (fa->magic != FASYNC_MAGIC) { |
| printk(KERN_ERR "kill_fasync: bad magic number in " |
| "fasync_struct!\n"); |
| return; |
| } |
| spin_lock_irqsave(&fa->fa_lock, flags); |
| if (fa->fa_file) { |
| fown = &fa->fa_file->f_owner; |
| /* Don't send SIGURG to processes which have not set a |
| queued signum: SIGURG has its own default signalling |
| mechanism. */ |
| if (!(sig == SIGURG && fown->signum == 0)) |
| send_sigio(fown, fa->fa_fd, band); |
| } |
| spin_unlock_irqrestore(&fa->fa_lock, flags); |
| fa = rcu_dereference(fa->fa_next); |
| } |
| } |
| |
| void kill_fasync(struct fasync_struct **fp, int sig, int band) |
| { |
| /* First a quick test without locking: usually |
| * the list is empty. |
| */ |
| if (*fp) { |
| rcu_read_lock(); |
| kill_fasync_rcu(rcu_dereference(*fp), sig, band); |
| rcu_read_unlock(); |
| } |
| } |
| EXPORT_SYMBOL(kill_fasync); |
| |
| static int __init fcntl_init(void) |
| { |
| /* |
| * Please add new bits here to ensure allocation uniqueness. |
| * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY |
| * is defined as O_NONBLOCK on some platforms and not on others. |
| */ |
| BUILD_BUG_ON(20 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( |
| O_RDONLY | O_WRONLY | O_RDWR | |
| O_CREAT | O_EXCL | O_NOCTTY | |
| O_TRUNC | O_APPEND | /* O_NONBLOCK | */ |
| __O_SYNC | O_DSYNC | FASYNC | |
| O_DIRECT | O_LARGEFILE | O_DIRECTORY | |
| O_NOFOLLOW | O_NOATIME | O_CLOEXEC | |
| __FMODE_EXEC | O_PATH | __O_TMPFILE |
| )); |
| |
| fasync_cache = kmem_cache_create("fasync_cache", |
| sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); |
| return 0; |
| } |
| |
| module_init(fcntl_init) |